Consecutive sentences are rare, but not unheard of, particularly with crimes of violence.

Johnson and his three co-defendants were charged with attacking and robbing several victims in St. Augustine on June 30.

One of the victims, a woman in her 60s, was severely beaten as she waited for a taxi on Riberia Street. She suffered multiple injuries and was taken to Flagler Hospital.

Photographs of the victim are in the file that Berger will review as she considers Johnson's sentence.

Johnson and his co-defendants another 15-year-old as well as a 13- and 16-year-old were arrested the day of the attacks.

The co-defendants already have pleaded to a total of eight offenses, Assistant State Attorney Adam Warren told the judge on Friday.

Seven of those charges are second-degree felonies, he said.

Johnson wore blue dress pants along with a red shirt and matching tie as he stood before the judge Monday morning. Appearing with the defendant was his grandmother, who has been appointed his guardian.

Warren told the judge that Johnson had not been offered a deal in exchange for his plea.

The state would make "no particular recommendation" for sentencing, either, Warren said.

Berger will decide if Johnson should be sent to a juvenile or adult institution.

Defense attorney Stephen J. Alexander asked the judge to explain the possible range of sentences to his client.

In addition to the possible 30 years for the charges he pleaded to on Monday, Johnson has pleaded to robbery and aggravated fleeing and eluding in another case.

That plea agreement called for a sentencing range from zero to 10 years in prison.

The judge gave Johnson no clues about the actual sentence she is contemplating.

She ordered Johnson to return to court on April 8 for sentencing.

The defendant is being held in the St. Johns County jail in a cellblock set aside for juveniles.